Struggling to resolve this code before my inspection is due. Here is the back story:

October 2021 302k miles:
Code popped up after replacing front struts with control arms and receiving a front end alignment. Clearly the code is not related so it was a surprise.

July 2022 308k miles:
Replaced the knock sensor harness that goes under the intake during a major top end reseal. Kept the original sensors as they looked okay at the time. Harness used was WVE 5S2254 from RockAuto.


December 2022 311k miles:
Replaced just the two knock sensors with NTK ID0166 from RockAuto. During disassembly found the Bank 2 sensor plastic socket cracked which broke apart completely while unplugging it. Had to dig it out of the harness!



Code came back about a week later. However now if the code comes back the CEL bulb will turn off after about 100 miles and the code will still be active in the system!

I tried using the Lexus troubleshooting flowchart but getting stuck. Appears the issue may either be with the parts I installed or the main harness going back to the ECU.

What does it mean if the CEL bulb is off but the code is permanent and currently in the system? The bulb works so I know it’s not burnt out.

 

I don't know. Every instance I've seen of this the code eventually lights the lamp. Pains me to say this but the only knock sensors that work are OEM. Two of them on Amayama will be about $220 shipped.

 

Hello,

It is quite strange, those Knock Sensor codes are pretty major errors, usually causing the engine to go into a severe limp mode. My best guess would be that the sensors are not completely failed, and it may be a very intermittent loss of contact somewhere for a very short time. One thing you can try is re-seating the connector for the wiring to the Knock sensor a couple of times, it may sand off some surface corrosion on the contacts, it can help a lot with older headlights that didn't have a seal in the connector from my experience, might as well be worth a try..

For what it worth, I do have to agree with LeX2K here, those are one fragile piece of technology, and even OEM ones can suffer shipping damage and what not, failing either right away or soon after. The good news is that I believe NTK gives a 2 year warranty for those sensors, so you may be able to claim a return on them to at least somewhat offset the cost of OEM sensors.

If you are not yet committed to taking the intake out again, you can try swapping the pins in the connector to see if the codes will shift to the other bank, which will tell if the problem area is on the ECU or the Sensor side. You can also try using a portable oscilloscope like the one linked below, but then I am not sure if it will really tell you that much, considering that the issue is likely intermittent.


Hope this helps and best of luck!

 

So this is exactly what I read in the Lexus service manual.

After I installed the new harness but before I did the new sensors, I crossed the pins at the connector and the code switched to P0325 which indicated the problem was at the sensors or harness. Since the harness was new, I went back and put new sensors in.

I will repeat the test again soon to see if it continues to jump from P0330 to P0325 when crossed. If it does, I’m at a loss.

For transparency, I did have a lot of issues with crumbling old insulation around the main engine harness above the Bank 1 valve cover. So I was wrestling it a lot and wrapping it in new TESA tape. And the old knock sensor harness was very brittle so I suspect wiring issues between the sensors and the ECU.

 

The only way you can know for sure is scope the signal right at the ECU connector. I know it sucks but otherwise you're doing the parts canon and/or guessing.

 

Okay that's what I was suspecting I need to do, because throwing parts at it is exactly what I wanted to avoid hence the service manual troubleshooting. Thank you for the guidance on this.

 

I just got done replacing my wiring harness and both knock sensors (along with a bunch of other stuff), as I had been getting a Bank 1 code. I used all Toyota original parts.

But the code started coming up a year ago, so for the last year, I had just wired the output of my Bank 2 sensor into both the Bank 1 & 2 inputs at the ECU and didn’t have any codes during that time, and performance seemed perfect. I know it’s a hack, but it could get you through inspection.